Giant freshwater stingray

Largest freshwater fish ever caught hooked in Cambodia

A fisherman caught the largest freshwater fish on record in northern Cambodia. It’s a giant stingray named Boramy (meaning “full moon” in the Khmer language) of a relatively unknown species. The massive female fish measured about 13 feet in length, weighing 661 pounds. It had roamed near an island on the Mekong River in the Stung Treng area. Scientists from the Wonder of Mekong project helped assess the creature, with the help of a dozen men to carry it to shore, before releasing it back home. According to their analysis, the stingray looked healthy with a good chance of continued survival.

Giant Stingray Becomes the Largest Freshwater Fish in the World

The scientists also placed a tag on the stingray to track its movements and are hopeful to learn more about it. This discovery “highlights how little we know about a lot of these giant freshwater fish,” said Zeb Hogan, a fish biologist at the University of Nevada. “You have a fish that’s now the record holder for the world’s largest freshwater fish, and we know little about it.” Despite not knowing much about them, this find proves this endangered species is still at large. 

giant freshwater stingray discovered in Mekong
Image Credit: Chhut Chheana | Wonders of the Mekong

The fisherman, Moul Thun, who made the catch, used a hook and line and contacted researchers soon after. Those working with the Wonders of Mekong were conveniently already in Cambodia, in the midst of a project to track the migration of fish in the river. “It’s a particularly healthy stretch of the river with a lot of deep pools — pools up to 90 meters deep,” said Hogan. “We started focusing on this area as a stretch of river that’s particularly important for biodiversity and fisheries, and as a last refuge for these big species.” 

Read: Rare Footage of Giant Phantom Jellyfish from 3,200 Feet Under the Sea

Stingrays are a Threatened Species

However, overfishing, pollution, and saltwater intrusion threaten the diverse fish population. Stingrays, giant and not, are particularly vulnerable to these issues, according to the Wonders of Mekong. So for the past several months, the team had told the local fisherman to look out for an unusual catch, particularly stingrays. Because they aren’t good fish food, the fishermen generally don’t try to catch them, although it can happen by accident, as in the case of Thun, who got paid market price for his find. [1]

But this giant stingray is a sign that the aquatic environment is still generally healthy despite all of the hardship it’s facing. “The Mekong’s deep pools sustain life far beyond these impressive giants. Spawning in this critical habitat produces billions of fish every year which ensure the food security and livelihoods for millions of people in Cambodia and Vietnam,” said Hogan. [2]

He added that Thun and the cooperation of the local fishermen were key to this research, and therefore should be considered allies when it comes to learning about and protecting these kinds of animals. Not much is known about the giant freshwater stingray, aside from key physical attributes. For instance, its mouth is about as big as a banana. Instead of teeth, it sports a unique type of “gripping pads” to crush its prey. “They’re on the bottom finding shrimps, mollusks, and small fish. They can suck them up with this banana-shaped mouth and crush them,” Hogan said. [3]

To Find and Conserve Large Freshwater Fish

Hogan has been on the hunt for the largest freshwater fish since 2005 when he began the Megafishes Project supported by the National Geographic Society. At that time, fishermen in Thailand found a 646-pound catfish in the Mekong River. But Hogan wondered if there were larger fish to fry. He became well-known as the host of National Geographic television’s Monster Fish show as he began searching all over the world. So far, he had been unsuccessful in finding a fish larger than the catfish that set him on this quest. Until Moul Thun caught Boramy.

However, the real goal was conservation, to protect these little-known yet endangered creatures. “It was  never about just finding the biggest fish,” Hogan said, “but looking for ways to protect these extraordinary animals that, in some cases, have been on Earth for hundreds of millions of years but were now drifting out of existence.”

Therefore, this discovery brings much hope, first as a potential location to find more giant stingrays and second as optimism that other threatened mega fish species are still thriving. “When people see that these animals exist, and begin to appreciate how incredible they are, they get inspired,” Hogan said. “I look at the fish that broke the record in 2005, and it was killed and sold for meat. Now we’re tracking the world’s largest freshwater fish. It’s such a contrast. It means that all is not lost.[4]

Keep Reading: Researchers Capture Rare Footage of Fish That Sees Through its Own Head


  1. “World’s biggest freshwater fish, a 660-pound stingray, caught in Cambodia.” CNN. June 21, 2022
  2. “World’s largest freshwater fish found in Mekong, scientists say.BBC. Grace Tsoi. June 20, 2022
  3. “Largest freshwater fish ever caught hooked in Cambodia.NBC News. Evan Bush. June 20, 2022
  4. “Enormous stingray sets world record for largest freshwater fish.National Geographic. Stefan Lovgren. June 20, 2022